If Kakashi is indeed dead there is no point in making Obito Tobi anymore. Because we would be pretty much the only people that knew him. Without Kakshi around it makes no sense to have Obito come back anymore.
But to answer the question of the TS, yes this theory has been around a very long time, yes many people thinks it's bogus..
it was never concluded that it's wrong. It could still turn out to be true if Kishi wants it to be, he has not cleared it up yet.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"